MPs have voted to seek an “alternative arrangement” to guarantee the Northern Ireland border stays open after Brexit.

But the Irish deputy prime minister has said “there are no credible alternative arrangements” to the proposal.

The backstop forms part of the withdrawal agreement negotiated by the UK and EU and is aimed at keeping the border between Northern Ireland and the Irish Republic open after Brexit.

BBC political correspondent Chris Mason said that while Mrs May pledged to “go back to Brussels to secure a plan that Parliament can stand behind”, the EU remains publicly opposed to changing the backstop.

The UK is due to leave the EU at 23:00 GMT on Friday 29 March, when the two-year time limit on withdrawal negotiations enforced by the Article 50 process expires.

Some MPs have suggested Britain will need more time to negotiate its exit to avoid crashing out of the EU without a deal.

What has the prime minister said?

Mrs May has insisted the departure date will not change, writing in the Telegraph that she would “deliver Brexit on time”.

And she said she rejected the suggestion “that seeking alternative arrangements for the backstop constituted ‘ripping up the Good Friday Agreement'”.

The prime minister added that MPs wanted the government to go back to Brussels to renegotiate the deal after the Commons voted in favour of Tory backbencher Sir Graham Brady’s amendment on Tuesday that called for “alternative arrangements” to be found.

Mrs May wrote: “While replacing the backstop with alternative arrangements was one option, [Sir Graham] would also be happy with the current backstop if there was a time limit or unilateral exit mechanism.”

What do cabinet ministers say?

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Media captionSajid Javid: Alternative Brexit backstop “can be done”

Home Secretary Sajid Javid told the BBC’s Andrew Marr Show that an alternative arrangement to the Irish backstop “can be done” using “existing technology”.

Mr Javid said: “I asked Border Force months ago to advise me to look at what alternative arrangements are possible and they’ve shown me quite clearly you can have no hard border on the island of Ireland and you can use existing technology – that is perfectly possible.